1. Field of the Invention
This invention relates generally to surgical apparatus and methods for repair of torn tissue, and more particularly to an apparatus and method for arthroscopic and other surgical repair of torn tissue and tissue reattachment by providing a system for suturing and anchoring the torn tissue, together, against other tissue substrates, or for attaching tissue to medical implants.
2. Description of Related Art
The rotator cuff is composed of four tendons that blend together to help stabilize and move the shoulder. When a tear occurs in the rotator cuff of the shoulder, it is often necessary to reattach the torn tendon or tendons to the bone of the humeral head. In a common prior art rotator cuff reattachment technique, the torn cuff is punctured by a punch, and prethreaded suture anchor screws (soft tissue fasteners) are drilled into the head of the humerus bone and the sutures threaded through the anchor screws are passed through the cuff in a difficult procedure using suture relay devices to pass the sutures through the tissue. After the suture strands are passed through the tissue, they are knotted and tied together to secure the reattached rotator cuff to the humerus head. Other types of prior art suture anchors are conically shaped members that are pressed into holes drilled into the bone and engage the cancellous mass surrounding the drilled hole.
A major problem with the above described suture anchoring technique is that the threaded suture anchor screws or conically shaped anchors are threadedly or otherwise secured to the cancellous bone mass beneath the near cortex of the head of the humerus, and depend on this cancellous mass for fixation. It is well known that the cancellous bone mass is susceptible to osteopenic changes (diminished amount of bone tissue).
As a result, the pull-out strength of suture anchors which are dependent on the cancellous bone mass beneath the cortex of the bone is subject to becoming diminished with time, and the anchors will tend to loosen, thereby possibly requiring a second operation to remove the loosened suture anchor.
Another problem with the conventional technique is that, in most cases, the sutures are not passed through the tissue when the anchor is set, and thus a difficult procedural step is required using devices such as punches and suture relays to pass and tie the sutures through the torn tissue.
Additionally, many anchor/suture devices require knots to be tied which is difficult with minimally invasive surgery and having a “knotless” solution is an advantage.
In my prior U.S. Pat. No. 6,491,714, an apparatus and method for arthroscopic repair of torn tissue such as a rotator cuff was taught wherein torn tissue such as a rotator cuff is positioned on the bone exterior by a tissue grasper. A cannula is inserted through the skin substantially to the torn tissue. A drill guide is inserted into the cannula, a drill bit is inserted into the drill guide, and a hole is drilled through the torn tissue and completely through the bone. The drill bit is removed and an inner cannula is passed through the drill guide until its distal end is engaged on the torn tissue or alternatively passed through the hole until its distal end is at the far end of the drilled hole. A soft tissue anchor having expandable wings at its distal end and sutures secured to an eyelet at its proximal end is releasably connected to the distal end of a tubular deployment tool with the free ends of the sutures extending through the deployment tool.
The deployment tool is passed through the inner cannula and a hole is drilled until the expandable wings clear the far end of the hole, a sufficient distance to allow the wings to expand to a diameter larger than the diameter of the drilled hole. The deployment tool, inner cannula, drill guide and cannula are removed and tension is applied to the suture to engage the expanded wings of the anchor on the exterior surface of the bone surrounding the drilled hole. A button is run down on the sutures through the cannula and secured on the torn tissue by the sutures such that the torn tissue is secured to the bone and the sutures are anchored to the hard exterior surface of the bone by the expanded anchor.
Unlike conventional soft tissues anchors which are anchored in the cancellous bone mass beneath the near cortex of the bone, the '714 teaching in one embodiment provides a suture anchor which is engaged on the exterior of the far cortex of the bone and completely bypasses the cancellous bone mass. The cortex of the bone is much less susceptible to osteopenia than the cancellous interior of the bone. The sutures are passed through the tissue when the anchor is set, and thus the difficult procedural step and use of devices such as punches and suture relays to pass and tie the sutures through the torn tissue is eliminated.
Calibrated markings on the '714 deployment system allow for precise measurement of the far cortex and precise measurement of the depth of insertion and engagement of the anchor device on the far cortex, such that structures beyond the cortex are not violated, and the button hold-down feature eliminates the traditionally difficult arthroscopic tying techniques.
In another broader aspect of the '714 invention, the surgical apparatus includes any form of a tissue substrate anchor of a conventional well-known structure, an elongated suture member securable at its proximal end to the anchor, and a separate torn tissue retainer which lockably engages as desired along the length of the suture member. The suture member extending through the torn tissue from the anchor and the tissue substrate. The torn tissue retainer is movable along the length of the exposed portion of the suture member until it is tightly positioned against the torn tissue and automatically locked in that position by non-reversible lockable engagement with the suture member. A separate tissue gripping member formed preferably as a semi-flexible plate or disc having a substantially larger surface area than the tissue retainer is also provided for enhanced retention of the torn tissue in place against the outer surface of the tissue substrate.
Still another broad aspect of this '714 invention is directed to a surgical apparatus which includes an integrally formed tissue substrate anchor having an elongated suture member formed as a unit therewith. A separate disc-shaped retainer lockingly engages with the exposed distal end of the suture portion at any desired point along the suture interlocking portion. The tissue retainer is therefore moveable along the length of the exposed engaging members of the suture member for tightening the tissue layer against the tissue substrate. Utilized another way, a tear such as that found within a torn meniscus may be reconnected utilizing this embodiment of the invention.
Currently, soft-tissue fixation products that utilize “knot-less” technology and screws rely on an “interference-fit” for holding power between the screw and bone. In general, non-screw anchors have a pullout strength near 200 newtons, and screws can have upwards of 400 newtons of pullout strength.
The patent technology allows for the introduction of a revolutionary type of anchor for soft-tissue fixation to bone. Screws, as opposed to hook-type anchors, have the strongest pullout strength, “ZIP-TIE” patented technology will introduce its technology to the eyelet of screws. Specifically, it will attach one member of the suture to screws and this will allow for a ratcheting of the suture member through the suture capture or retainer or suture anchor, thereby creating a very strong construct.
The traditional repair of soft tissue requires sutures to be passed through the tissue. A knot is tied, which holds the torn tissue together, allowing for healing. Minimally invasive surgical techniques are being utilized through “button-hole” size incisions. Surgery is performed with instruments that pass through cannulas (like drainage culverts or pipes). Knots that would be utilized for this type of repair are tied and must be slid down through these cannulas. This technique can be difficult, result in adequate repair strength, provide for poor tissue approximation, for some surgeons, it may result in an inability to proceed with a minimally invasive approach secondary to the advanced technical difficulty, and finally, can add significant operative time to surgical procedures. USCO's patented technology is akin to a “cable or tie-wrap” that is utilized for holding electric wire or cables together. Based upon the patented interface, a “pipe-line” of products will be created using knot-less, self-locking interface as a technology development platform.
The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those skilled in the art upon a reading of the specification and a study of the drawings.